Therefore, to elucidate the relationships between HHLA2 expression and PD-L1 and B7x expression in ovarian cancer, the CCLE database was used to analyse the mRNA levels of HHLA2, PD-L1, and B7x in 47 ovarian cancer cell lines using Spearman’s correlation analysis. This evidence concerns the gene HHLA2 and ovarian carcinoma.